Interpolated timestamps in high-speed data capture and analysis

• US 20060248106A1
• Filed: 03/17/2005
• Published: 11/02/2006
• Est. Priority Date: 03/17/2005
• Status: Active Grant

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: JDS Uniphase Corporation (Lumentum Holdings Inc.)
• Inventors: Milne, Andrew James, Gentieu, Paul
• Granted Patent: US 7,779,340 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 43/0847 Transmission error
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps

Abstract

Methods and apparatuses for using interpolation to associate timestamp values to data received in a data capture and analysis system. An analysis processor receives data representing data transferred in a communications link. The analysis processor also receives timestamp signals. The analysis processor performs an interpolation between at least two timestamp values received and associates results of the interpolation with the data. The analysis processor analyzes the data. A logic device can be coupled to the analysis processor to interleave timestamp signal values with the data and transmit the interleaved data and timestamp signals to the analysis processor.

Claims

1. A data capture and analysis device, comprising:

an interface configured to receive data;

an interface configured to receive periodic timestamps; and

a processor configured to receive the data and the timestamps and perform an interpolation between at least two timestamps and associate results of the interpolation with at least portions of the data.

2. The device of claim 1, further comprising a tap for receiving the data, wherein the data represents data communicated in a communications link, network link, or wireless link.

3. The device of claim 1, wherein the processor or a different processor analyzes the data.

4. The device of claim 3, wherein the processor that analyzes the data analyzes the data for at least one of protocol conformity errors, packet decoding errors, 10 bit conversion errors, 8 bit conversion errors, running disparity verification, CRC validation, identification of passwords, Voice over IP, virus activity, and performance issues.

5. The device of claim 3, further comprising:

a logic device configured to receive the data and transmit the data to the analysis processor, wherein the logic device is further configured to transmit the periodic timestamps to the analysis processor.

6. The device of claim 5, wherein the logic device is further configured to receive a clock signal, wherein the periodic timestamps are based at least in part on the clock signal received by increasing the frequency of the clock signal.

7. The device of claim 5, wherein the logic device is further configured to interlace the periodic timestamps with the data.

8. The device of claim 3, further comprising:

at least one of a computer readable media coupled to the analysis processor for storing the data, the periodic timestamps, and a result of the interpolation and an output device for presenting a result of the analysis to a user.

9. The device of claim 1, wherein the data capture and analysis device is configured to capture data at a rate between about 1 Gbps and 10 Gbps.

10. A method for associating timestamps to data received by a data analysis apparatus, the method comprising:

receiving a first timestamp;

receiving a second timestamp;

receiving a plurality of transferred data records, the plurality of transferred data records including a first data record associated with the first timestamp and a second data record associated with the second timestamp, the plurality of transferred data records further including intermediate data records that are received intermediate to the first and second data records; and

calculating intermediate timestamp values using interpolation of the first and second timestamp signals, wherein the intermediate timestamp values are intermediate to the first and second timestamp signals.

11. The method of claim 10, further comprising:

associating the intermediate timestamp values with the intermediate data records.

12. The method of claim 10, further comprising:

storing at least one of the timestamp signals, the intermediate timestamp values, the first data record, the second data record, and the intermediate data records in at least one computer readable memory.

13. The method of claim 10, further comprising:

interlacing the first and second timestamp signals with the plurality of data records.

14. The method of claim 10, wherein the intermediate timestamp values are calculated at least in part using at least one of linear interpolation, non-linear interpolation, and extrapolation.

15. The method of claim 10, wherein the interpolation takes into account compression of the data records.

16. The method of claim 10, wherein the plurality of data records is equal to 128 data records, wherein the first data record is the first received data record of the plurality of data records and the second data record is the 128th received data record of the plurality of data records.

17. A method for capturing and analyzing data communicated in a communications link comprising:

receiving a first timestamp;

receiving a second timestamp;

receiving a plurality of data records;

calculating intermediate timestamps that are intermediate to the first timestamp and the second timestamp using interpolation between the first timestamp and the second timestamp;

associating one or more of the intermediate timestamps with one or more of the plurality of data records; and

conducting analysis of the data records.

18. The method of claim 17, further comprising:

presenting a result of the analysis to a user.

19. The method of claim 17, further comprising:

interlacing the first and second timestamps with the plurality of data records.

20. The method of claim 19, wherein the first and second timestamps are interlaced by a programmable logic device, and wherein the analysis is conducted by an analysis processor that includes computer executable instructions that when executed by the analysis processor cause the analysis processor to analyze the data records for at least one of protocol conformity errors, packet decoding errors, 10 bit conversion errors, 8 bit conversion errors, running disparity verification, CRC validation, identification of passwords, Voice over IP, virus activity, and performance issues.